The Big Collodion Test we go! Yesterday I’ve shot 12 plates (2 plates were to determine exposure time) of 5 different collodion formulas and 2 developer formulas. Please keep in mind this test is performed under my specific conditions, with my chemistry, age of silver bath etc etc so all conclusions that I draw here may not be consistent with your findings or may not turn out the same when you give them a go.

Having learned that a formula is just a formula and has to be adjusted according to specific circumstances (temp, humidity, age of silver bath, amount of alcohol used etc etc) this is by no means a ‘scientific’ test or whatsoever, merely meant for me to see how a 2 salted collodion will compare to a 4 salted collodion, if I would gain anything in speed from one of the formulas and how the tonal range would vary. Anyway, enough of this diplomatic stuff 😉

The difference in developer is not really that interesting, the difference you might see may just as well be caused by flowing too much developer over the plate, wiping off some of that precious silver thus changing the result. I used the Osterman developer and the Lea’s Sugar developer (for the exact formulas see this former post). The latter because of the amount of restrainer used (sugar) might be interesting to use in hot conditions so I’ll surely be bringing it out when summer hits our land to see how it fares. I’ll post all of the photos anyway, if you’d like to have them mailed to you to give them a closer look, shoot me an email and I’ll send them to you.

Above the test setup I used to make the photos. A lot of different colors to see how they would come out on the plates. A color chart and a grey scale to check out tonal range and dynamic range. Orange carrots and orange mandarins, oh how different they look on the plates!

Specific Circumstances of the Test:
Silver bath – Specific Gravity: 1,06
Silver bath – Acidity: 4,5 -5
Silver bath – Age: +- 2,5 years old

Temperature: 17,6 degrees
Humidity: 51%

Fixer: Sodium Thiosulfate 30% (I can’t stand the smell of KCN so never use this indoors at home)
Lighting: 2 Falcon Eyes 928 lights in an approx. angle of 45 degrees on the subject, 1 on each side.

Medium: 4×5″ Black Glass Ambrotypes
Lens: Steinheil 230mm
Aperture: f/5,6

All the plates are unvarnished as I didn’t want to run the risk of screwing up plates 😉

1 New Guy Collodion - My standard developer - 35 seconds exposure time
2 New Guy Collodion - Osterman Developer - 35 seconds exposure time
3 Lea's Landscape #7 No Additional Ether - Osterman Developer - 35 seconds exposure time
4 Lea's Landscape #7 No Additional Ether - Lea's Sugar Developer - 35 seconds exposure time
5 Lea's Traditional Landscape #7 - Osterman Developer - 35 seconds exposure time
6 Lea's Traditional Landscape #7 - Lea's Sugar Developer - 35 seconds exposure time
7b Old Workhorse Fast Clear - Osterman Developer - 17 seconds (!) exposure time
8 Old Workhorse - Sugar Developer - 17 seconds (!) exposure time
9 Two-salted Collodion, No CadmiumBromide - Osterman Developer - 35 seconds exposure time
10 Two-salted Collodion, No CadmiumBromide - Sugar Developer - 35 seconds exposure time

I don’t have much to say about No.1 +2. This is the formula I’ve used exclusively until now.
No. 3+4 are the etherless versions and the first thing that I noticed was that with both plates I have an inconsistency in the background at about the same locations. They are the only two plates that have this. On the scan it is not that apparent but on the plates it is.

The plates that really stood out to me are No. 7b+8. No. 7 + 7a were over exposed as you can imagine. 7b is still on the light side so it saves me over HALF the exposure time, at least one stop that is. For studio use this will definitely be the one I’ll be working with. For outside use it’s probably a bit too fast, or I’ll have to stop down the lens of course but I might give Lea’s Traditional Landscape a go and the OWH.

The plates that surprised me the most are No. 9+10. This particular formula didn’t clear at all. Lot’s of undissolved salts at the bottom of the bottle which I decanted before using. I also filtered this collodion version before use but didn’t make much of a difference in the clearing part. I didn’t expect anything from it when using so I was surprised something came up on the plate. I should’ve dissolved the salts first in water before mixing with the alcohol and ether (stupid me) but it worked nonetheless.

Another thing that’s odd on plate 9+10 is that the SUN bottle on 9 is much lighter than on 10. Seeing that this is the only thing coming out much lighter it’s probably a flaw in my development, having poured off some of the silver with the developer. This is however my best guess as to what has happened there. I don’t recall the exact development, curiosities etc anymore from these plates.

For people not eager to work with Cadmium Bromide this is a proper way to go I guess. It’s a contrasty plate, pretty even all over and compared to the other formulas (except the OWH) comparable in speed. It also gave the most detail in the SUN bottle of all the other plates, together with 1 +2.

The plates developed with the Osterman formula seem the most consistent which gives cleaner more even plates (except with the Lea’s traditional formula, sugar is also fine). It’s a developer I’ll take as a starting point from now on and learn how to adjust it when needed.

Well, there you have it. I hope you enjoyed this overview, I sure did! Doing the testing was a good thing to do for me. I now have a good place to start from and I’m really happy to have found a formula which gives me shorter exposure times with good tonality.

Maybe I’ve forgotten things which I may add or adjust in the future. Thanks for looking and have a great weekend!

– 🙂 –


  1. can you account for the difference of tonality of the sun bottle between plates 9 and 10? the only difference seems to be the developer, yet in plate 10 the blue is rendered as a very deep black. btw, great insights and thanks for doing the test.

    1. Hi,

      Thanks for your comment. The difference between these is indeed quite big. Seeing that pretty much only the SUN bottle has been affected I think it’s a flaw in my development of the plate. I probably poured off to much silver where the bottle was at resulting in a lighter part on the plate. This is a guess though, I can’t recall anymore how the development went exactly. They were the last plates in the test and I was getting tired…

      Great to hear you enjoyed the test!


  2. Thanks, Indra. This was most informative. Now I will go back in your previous posts to see the different formulas. I’ve thought about taking our gear to school and running similar experiments with my science students. I think it would make science and history come alive for them through this historic process. Maybe you have inspired me.

    1. Thank you Maire! That’s the best compliment I can get 😉
      I’ve added a link in the test to the post where the exact formulas are at. Makes it a bit easier to look it up. Have fun with your students. I think showing science and history with the use of real examples always helps bringing it back to life and make it appeal more to people. History speaks!

  3. A nice work as well as ambitous. My eloge to you.

    Checked Oestemans developer formula vs Quinns . There different is about 30% more ethanol and glacial acetic acid in Oestrmanns dev. This means if I understand this correctly O’s will be more restrained and have increased flowing properties on the collodium surface at development.

    Even if there is clear differences in results they are smaller than I expected compared to the variation you had in choosen recipies.

    Do you share my opinions?

    1. Hi Christer,

      Thank you!

      The acid works as a restrainer and that’s exactly what I was looking for. I found the developer I normally use (Quinn’s version) developing the plate too fast for me. The alcohol makes it flow over the plate really well. Maybe that’s what causes a more even development but I’m not sure. Didn’t test all the different collodion formulas with Quinn’s developer as I knew I didn’t want to continue using that.

      The differences are indeed quite small. From some other comparative images I saw I thought the difference would be bigger but Jeroen de Wijs already told me that they would be relatively small. Nr. 7b and 8 really surprised me in that regard.

      As Mark Osterman also explained to me, I think it’s not so much about the specific formula but rather how it fits in your workflow. For example, if your silver bath is older and contains more alcohol from your plates you have to compensate this with more alcohol in your developer.

      I’m still working on this in my head but I think it’s more about adjusting the developer and such according to your specific circumstances that just simply a standard formula to get the best results. I think this test has proven this. Now it’s all about the fine-tuning.

      It could very well be that when working outside in the heat you’ll notice more differences in how the collodion responses to the environmental changes, heat and humidity, peeling issues etc. Unfortunately summer still feels miles away so can’t try that now. I’ll probably try the lea’s Landscape #7 outside to see what it gives me. I’m looking for a better tonal range in leaves and bushes etc.

      Anyway, glad you dig the test and thanks for sharing your insights!


      1. I think your work is important to show that emotions regarding if this or that recipy is the best is of less interest. The importance lies in the ability to translate the conditions of your chemistry and ambient into your intent of subject matter. If a scene looks in a certain way and temperature low or high you should change chemistry in a certain way.

        Well I guess wheather is pretty the same in Sweden = monsun time. I’m eager to take my recently finnished dark room box outside. If not I might need to invest in a pair of Falcon Eyes 😉


      2. Hi Christer,

        Yes, you’re right. That is indeed the most important conclusion I draw from my tests. Hope the weather will be better for you soon! Good luck with your dark box. It’s really fun and rewarding working outside in the field. But, in winter time the Falcon Eyes lights are VERY handy indoors 😉 I love them!


  4. Bonjour Indra et merci pour votre générosité dans le partage de vos tests… j’ai 2 questions, le temps de développement était il constant avec toutes les plaques ? combien de secondes ? je cherche une combinaison pour avoir le moins de contraste possible… c’est difficile a voir sur les photos du test… merci encore. jean-françois Cholley

    Good morning Indra and thank you for your generosity in the distribution of your tests. I have 2 questions, the time of development was it constant with all plates? how much seconds? I search a combination to have least possible contrast it is difficult has see on the photographs of your test, thanks again. jeans-françois Cholley

    1. Bonsoir Jean-Francois,

      De rien, c’était mon plaisir 😉
      Le temps de développement était approximativement le même que toutes les plaques; 12 secondes.
      Bonne chance avec votre recherche!


  5. Hi Indra!

    I’m arriving a little late to the conversation, but I wanted to ask you about the formulas for collodion without cadmium bromide. We are working in Argentina and we haven’t been able to find cadmium bromide and probably won’t be able to find it. What we have is the following formula, can you tell me what you think about it?

    1 liter Collodion 2%
    15 grams ammonium iodide
    10 grams potassium iodide
    5 grams ammonium bromide

    Any input is much appreciated.

    Thanks in advance! We have found some great information on your site

    1. Hi Meghan,

      Very sorry for the late reply, I was in Austria when you posted this and didn’t find the time earlier to reply.

      What kind of collodion do you use?
      I use the USP 4% and further dilute it with ethanol and ether.

      I have found ammonium to speed up the exposure time but to cause striations in my images, which show especially with making negatives. I quit using that. When I want speed, I shoot film, or in worst case scenario, digital 😉

      I use the basic formula from Scully & Osterman which I find to work nicely for me. The formula of which collodion version you use is not even that important on its own. It’s which developer you use with it, the fixer (strength), the way your silver bath is, they all form a harmonic combination depending on what circumstances your working in (humidity, temperature etc.) instead of merely standing on their own.

      If you have any questions feel free to ask!



  6. Indra, My take on what’s happening with plates 9 & 10 is that potassium bromide has precipitated from the formula leaving an excess of iodide. A collodion with a higher ratio of iodide:bromide will be less spectrally sensitive and more contrasty according to all I have read. So, if your salt combination was either KBr + KI, KI+ NH4BR, or any other bromide combined with a potassium salt, KBr will precipitate and the collodion should become less sensitive to cyans and green and also increase in contrast. George Berkhofer (sp?) even goes so far in his manual to suggest that use of any potassium salt is wasteful. Of course, many formulas contain KBr or KI and people use them successfully. Their results probably have more contrast than a similar formula mixed the same day but excluding potassium in the formula. Considering that some formulas are initially low in contrast until they have ripened for a few days, and a new silver bath may exaggerate that low contrast problem unless the bath has been properly seasoned, folks may be liking a formula that counteracts these effects by including potassium salts.

    Great information in your post.

    1. Hi Smieglitz,

      I wanted to get back to you much sooner than I did but I wanted to take the time to properly read your write-up. I only used potassium salts in that specific formula namely Potassium Iodide and Potassium Bromide. What you say could very well be. Might be that when you work outside in the field with trees, leaves etc. the tonal range is less as it can’t properly record the greens. That might make it seem like the contrast is higher while in fact it omits subtleties in the tonal range.

      Out of curiosity, what formula do you use? I now use Osterman’s Basic Formula with Cadmium Bromide and Potassium Iodide. I find it to my liking.

      Thank you for your extended comment!



    1. Thanks Peter 😉
      It was quite a bit of work to do this and it taught me pretty much one thing; a formula is just a formula and needs a person to make it work.
      Great to see you keep coming back and enjoy my blog!

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